What would you send to yourself 2-3 months into a solo trip

Hello! I’m leaving on an indefinite trip to Europe next week and trying my best to one bag it. I have a backpack filled with my necessary electronics, clothes and an extra pair of shoes etc but I have two friends that are planning on meeting up with me in June/July.

Not sure if they both will but fairly confident one of them would; and I’m trying to figure out if it would be a good idea to pack a large ziploc bag of things they could bring me and I’m not sure yet what I’d need come June.

Thoughts are:

Extra pair of socks and underwear

Pair of shorts? (brining one already)

Maybe few bags of my favourite tea

Small book? (Bringing a Kobo with me)

Is there anything you find you like a refresh of a few months into your trip? Wondering how helpful a little extra something to swap out spring to summer would be.

Thanks for your help!